<?xml version="1.0"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html><head><title>SASAPI</title><script src="../../../quicknav.js" type="text/javascript"></script><script><!--
document.quicknavBasePath="../../../index-files";
//--></script><link href="../../../style.css" title="JavaDoc" rel="stylesheet" type="text/css"/><link href="../../../unnatural.css" title="Unnatural" rel="alternate stylesheet" type="text/css"/><link href="../../../overview-summary.html" title="Overview" rel="top"/><meta name="generator" content="http://www.badgers-in-foil.co.uk/projects/as2api/"/></head><body><pre><span class="lineno" id="1">     1  </span><span class="comment doc">/**
<span class="lineno" id="2">     2  </span> * com.sekati.crypt.LZW
<span class="lineno" id="3">     3  </span> * @version 1.0.3
<span class="lineno" id="4">     4  </span> * @author jason m horwitz | sekati.com
<span class="lineno" id="5">     5  </span> * Copyright (C) 2007  jason m horwitz, Sekat LLC. All Rights Reserved.
<span class="lineno" id="6">     6  </span> * Released under the MIT License: http://www.opensource.org/licenses/mit-license.php
<span class="lineno" id="7">     7  </span> * 
<span class="lineno" id="8">     8  </span> * Sourced from ascrypt for dependencies only - version 1.1, author Mika Pamu
<span class="lineno" id="9">     9  </span> * Original Flash port by Ash &amp; Lalek &amp; Shoebox and others.
<span class="lineno" id="10">    10  </span> * @see http://www.razorberry.com/blog/archives/2004/08/22/lzw-compression-methods-in-as2/
<span class="lineno" id="11">    11  </span> * @see http://www.lalex.com/blog/comments/200405/164-compression-lzw-actionscript-2.html
<span class="lineno" id="12">    12  </span> */</span>
<span class="lineno" id="13">    13  </span>
<span class="lineno" id="14">    14  </span><span class="key">import</span> com.sekati.crypt.ICipher;
<span class="lineno" id="15">    15  </span>
<span class="lineno" id="16">    16  </span><span class="comment doc">/**
<span class="lineno" id="17">    17  </span> * Compresses and decompresses text with the LZW algorithm.
<span class="lineno" id="18">    18  </span> */</span>
<span class="lineno" id="19">    19  </span><span class="key">class</span> com.sekati.crypt.LZW <span class="key">implements</span> ICipher {
<span class="lineno" id="20">    20  </span>
<span class="lineno" id="21">    21  </span>	<span class="comment doc">/**
<span class="lineno" id="22">    22  </span>	 * Compresses the specified text.
<span class="lineno" id="23">    23  </span>	 * @param src (String)
<span class="lineno" id="24">    24  </span>	 * @return String
<span class="lineno" id="25">    25  </span>	 */</span>
<span class="lineno" id="26">    26  </span>	<span class="key">public</span> <span class="key">static</span> <span class="key">function</span> compress(src:String):String {
<span class="lineno" id="27">    27  </span>		<span class="key">var</span> chars:Number = <span class="num_const">256</span>;
<span class="lineno" id="28">    28  </span>		<span class="key">var</span> original:String = src;
<span class="lineno" id="29">    29  </span>		<span class="key">var</span> dict:Array = <span class="key">new</span> Array( );
<span class="lineno" id="30">    30  </span>		<span class="key">var</span> i:Number;
<span class="lineno" id="31">    31  </span>		<span class="key">var</span> xstr:String;
<span class="lineno" id="32">    32  </span>		<span class="key">for</span> (i = <span class="num_const">0</span>; i &lt; chars ; i++) dict[String( i )] = i;
<span class="lineno" id="33">    33  </span>		<span class="key">var</span> result:String = <span class="key">new</span> String( <span class="str_const">""</span> );
<span class="lineno" id="34">    34  </span>		<span class="key">var</span> splitted:Array = original.split( <span class="str_const">""</span> );
<span class="lineno" id="35">    35  </span>		<span class="key">var</span> buffer:Array = <span class="key">new</span> Array( );
<span class="lineno" id="36">    36  </span>		<span class="key">for</span> (i = <span class="num_const">0</span>; i &lt;= splitted.length ; i++) {
<span class="lineno" id="37">    37  </span>			<span class="key">var</span> current:String = splitted[i];
<span class="lineno" id="38">    38  </span>			<span class="key">if</span> (buffer.length == <span class="num_const">0</span>) xstr = String( current.charCodeAt( <span class="num_const">0</span> ) );
<span class="lineno" id="39">    39  </span>			<span class="key">else</span> xstr = buffer.join( <span class="str_const">"-"</span> ) + <span class="str_const">"-"</span> + String( current.charCodeAt( <span class="num_const">0</span> ) );
<span class="lineno" id="40">    40  </span>			<span class="key">if</span> (dict[xstr] !== undefined) {
<span class="lineno" id="41">    41  </span>				buffer.push( current.charCodeAt( <span class="num_const">0</span> ) );
<span class="lineno" id="42">    42  </span>			} <span class="key">else</span> {
<span class="lineno" id="43">    43  </span>				result += String.fromCharCode( dict[buffer.join( <span class="str_const">"-"</span> )] );
<span class="lineno" id="44">    44  </span>				dict[xstr] = chars;
<span class="lineno" id="45">    45  </span>				chars++;
<span class="lineno" id="46">    46  </span>				<span class="key">delete</span> buffer;
<span class="lineno" id="47">    47  </span>				buffer = <span class="key">new</span> Array( );
<span class="lineno" id="48">    48  </span>				buffer.push( current.charCodeAt( <span class="num_const">0</span> ) );
<span class="lineno" id="49">    49  </span>			}
<span class="lineno" id="50">    50  </span>		}
<span class="lineno" id="51">    51  </span>		<span class="key">return</span> result;
<span class="lineno" id="52">    52  </span>	}
<span class="lineno" id="53">    53  </span>
<span class="lineno" id="54">    54  </span>	<span class="comment doc">/**
<span class="lineno" id="55">    55  </span>	 * Decompresses the specified text.
<span class="lineno" id="56">    56  </span>	 * @param src (String)
<span class="lineno" id="57">    57  </span>	 * @return String 
<span class="lineno" id="58">    58  </span>	 */</span>
<span class="lineno" id="59">    59  </span>	<span class="key">public</span> <span class="key">static</span> <span class="key">function</span> decompress(src:String):String {
<span class="lineno" id="60">    60  </span>		<span class="key">var</span> chars:Number = <span class="num_const">256</span>;
<span class="lineno" id="61">    61  </span>		<span class="key">var</span> dict:Array = <span class="key">new</span> Array( );
<span class="lineno" id="62">    62  </span>		<span class="key">var</span> i:Number;
<span class="lineno" id="63">    63  </span>		<span class="key">for</span> (i = <span class="num_const">0</span>; i &lt; chars ; i++) {
<span class="lineno" id="64">    64  </span>			<span class="key">var</span> c:String = String.fromCharCode( i );
<span class="lineno" id="65">    65  </span>			dict[i] = c;
<span class="lineno" id="66">    66  </span>		}
<span class="lineno" id="67">    67  </span>		<span class="key">var</span> original:String = src;
<span class="lineno" id="68">    68  </span>		<span class="key">var</span> splitted:Array = original.split( <span class="str_const">""</span> );
<span class="lineno" id="69">    69  </span>		<span class="key">var</span> buffer:String = <span class="key">new</span> String( <span class="str_const">""</span> );
<span class="lineno" id="70">    70  </span>		<span class="key">var</span> chain:String = <span class="key">new</span> String( <span class="str_const">""</span> );
<span class="lineno" id="71">    71  </span>		<span class="key">var</span> result:String = <span class="key">new</span> String( <span class="str_const">""</span> );
<span class="lineno" id="72">    72  </span>		<span class="key">for</span> (i = <span class="num_const">0</span>; i &lt; splitted.length ; i++) {
<span class="lineno" id="73">    73  </span>			<span class="key">var</span> code:Number = original.charCodeAt( i );
<span class="lineno" id="74">    74  </span>			<span class="key">var</span> current:String = dict[code];
<span class="lineno" id="75">    75  </span>			<span class="key">if</span> (buffer == <span class="str_const">""</span>) {
<span class="lineno" id="76">    76  </span>				buffer = current;
<span class="lineno" id="77">    77  </span>				result += current;
<span class="lineno" id="78">    78  </span>			} <span class="key">else</span> {
<span class="lineno" id="79">    79  </span>				<span class="key">if</span> (code &lt;= <span class="num_const">255</span>) {
<span class="lineno" id="80">    80  </span>					result += current;
<span class="lineno" id="81">    81  </span>					chain = buffer + current;
<span class="lineno" id="82">    82  </span>					dict[chars] = chain;
<span class="lineno" id="83">    83  </span>					chars++;
<span class="lineno" id="84">    84  </span>					buffer = current;
<span class="lineno" id="85">    85  </span>				} <span class="key">else</span> {
<span class="lineno" id="86">    86  </span>					chain = dict[code];
<span class="lineno" id="87">    87  </span>					<span class="key">if</span> (chain == undefined) chain = buffer + buffer.slice( <span class="num_const">0</span>, <span class="num_const">1</span> );
<span class="lineno" id="88">    88  </span>					result += chain;
<span class="lineno" id="89">    89  </span>					dict[chars] = buffer + chain.slice( <span class="num_const">0</span>, <span class="num_const">1</span> );
<span class="lineno" id="90">    90  </span>					chars++;
<span class="lineno" id="91">    91  </span>					buffer = chain;
<span class="lineno" id="92">    92  </span>				}
<span class="lineno" id="93">    93  </span>			}
<span class="lineno" id="94">    94  </span>		}
<span class="lineno" id="95">    95  </span>		<span class="key">return</span> result;
<span class="lineno" id="96">    96  </span>	}
<span class="lineno" id="97">    97  </span>
<span class="lineno" id="98">    98  </span>	<span class="key">private</span> <span class="key">function</span> LZW() {
<span class="lineno" id="99">    99  </span>	}
<span class="lineno" id="100">   100  </span>}</pre><ul class="main_nav" id="main_nav"><li><a href="../../../overview-summary.html" title="Overview of SASAPI" class="button">Overview</a></li><li><a href="package-summary.html" title="Overview of package com.sekati.crypt" class="button">Package</a></li><li><a href="LZW.html" title="Detail of com.sekati.crypt.LZW API" class="button">Class</a></li><li><span class="button nav_current">Source</span></li><li><a href="../../../index-files/index.html" title="Alpabetical index of types and members" class="button">Index</a></li></ul><div class="footer"><a href="http://www.badgers-in-foil.co.uk/projects/as2api/" title="ActionScript 2 API Documentation Generator">as2api</a></div></body></html>